where \(\beta _{\mathrm {Bu}}\)  denotes the Rician factor, and \({\bf H}^{\mathrm {LoS}}\)  and \({\bf H}^{\mathrm {NLoS}}\)  denote the LoS and Rayleigh fading components, respectively. Note that \({\bf H}\)  is equivalent to a LoS channel when \(\beta _{\mathrm {Bu}} \rightarrow \infty \) , and a Rayleigh fading channel when \(\beta _{\mathrm {Bu}} =0\) . Then, \({\bf H}\)  is multiplied by the square root of the distance-dependent path loss \({f_{\rm d}}({d_{\rm Bu}})\)  in (REF ). Similarly, the BS-RIS and RIS-user channels can also be generated by the above procedure, and let \(\beta _{\mathrm {BR}}\)  and \(\beta _{\mathrm {Ru}}\)  denote the Rician factors of them, respectively. Here we assume \(\beta _{\mathrm {BR}}\rightarrow \infty \) , \(\beta _{\mathrm {Bu}}=0\)  and, \(\beta _{\mathrm {Ru}}=0\)  [1]}.
